Gender and the Heart: Sex-Specific Differences in Normal Myocardial Anatomy and Physiology and in the Experiences of Some Diseases of the Cardiovascular System

This chapter reviews some of the differences between men and women's normal cardiac physiology and describes some differences in their unique experiences with common diseases of the cardiovascular system. Women's hearts and coronary arteries are generally smaller than that of their male counterparts because women's bodies are smaller as compared to that of men. According some researchers, small vessel size is a predictor of increased risk of in-hospital mortality in patients undergoing coronary artery bypass grafting, in both sexes, and found that sex was an important predictor of coronary size. Investigators have studied myocyte death in congestive heart failure and noted a significant impact of gender on the process. Sex-specific differences in the properties of the myocardium have prompted a widely held hypothesis that the hormonal milieu of men and women modulates not only the functional characteristics of the cardiovascular system, but is also the reason that premenopausal women are relatively less likely to develop coronary artery disease. The activity of the renin-angiotensin system in males and females is different and is complexly affected by estrogen. Electrophysiological differences in men and women are well described. Women have a faster resting heart rate than men. There are differences in autonomic nervous system activity in men and women that influence cardiac rates and rhythms.